This invention relates to abrasive tools.
The complete specification of United Kingdom Patent Publication No. 2158086 discloses an abrasive tool having a working portion which includes an abrasive insert held therein, that insert being exposed to high temperature during manufacture or use of the tool and comprising a mass of diamond particles present in an amount of 80 to 90 percent by volume of the insert and a second phase present in an amount of 10 to 20 percent by volume of the insert, the mass of diamond particles containing substantial diamond-to-diamond bonding to form a coherent skeletal mass and a second phase consisting essentially of silicon, the silicon being in the form of silicon and/or silicon carbide. Examples of such tools are dressing tools, turning tools and surface set or impregnated drill bits.
It is stated in the complete specification of this application that the abrasive inserts may take on a variety of shapes depending on the use to which they are put. Examples of suitable shapes are said to be disc, triangular, cube, rectangular and hexagonal. The illustrated embodiments utilise abrasive inserts which are of triangular and cube shape.
The abrasive inserts are useful in the applications referred to above because they are thermally stable and have considerable strength. Examples of other thermally stable abrasive bodies are those described in U.S. Pat. No. 4,224,380 and the complete specification of South African Pat. No. 84/0053.